Method and apparatus for producing textured yarn

ABSTRACT

A method for producing textured yarn wherein yarn is drawn through a heating zone, then a cooling zone, and then at least partially around an idler grooved roll which has its axis of rotation at an angle other than a right angle to the direction of yarn travel, and finally delivered from the treatment area. In passing around the grooved roll, the yarn drives the grooved roll and first contacts one side surface of the groove above the bottom, then moves down into the groove bottom, and finally up the opposite side wall before leaving the roll surface. Apparatus is disclosed schematically in the form of a drawtwister, with the drawtwister feed roll serving as the means to feed yarn to the texturing means, and the drawtwister draw roll serving as the means for delivering the yarn from the treatment area.

United States Patent 91 Edwin et al.

[ Jan. 1,1974

[ METHOD AND APPARATUS FOR PRODUCING TEXTURED YARN [75] Inventors: John J. Edwin, Charlotte, N.C.; J.

Milton Lathem, Gainesville, Ga.

[52] US. Cl. 57/34 HS, 57/77.4, 57/157 TS [51] Int. Cl. D02g 1/04 [58] Field of Search 57/34 R, 34 HS, 77.4,

[56] References Cited UNITED STATES PATENTS 3,094,834 6/1963 Deeley et al 57/5l.6 X

3,680,302 8/1972 Hess et al. 57/77.4 X

' 3,668,856 6/1972 Richter 57/77.4

3,327,461 6/1967 Wyatt 57/77.4

3,296,786 1/1967 Wyatt 57/77.4 X

3,026,668 3/1962 Latimer 57/77.4

Primary ExaminerDonald E. Watkins Attorney-Thomas B. Van Poole et al.

[ 5 7 ABSTRACT A method for producing textured yarn wherein yarn is drawn through a heating zone, then a cooling zone, and then at least partially around an idler grooved roll which has its axis of rotation at an angle other than a right angle to the direction of yarn travel, and finally delivered from the treatment area. 1n passing around the grooved roll, the yarn drives the grooved roll and first contacts one side surface of the groove above the bottom, then moves down into the groove bottom, and finally up the opposite side wall before leaving the roll surface. Apparatus is disclosed schematically in the form of a drawtwister, with the drawtwister feed roll serving as the means to feed yarn to the texturing means, and the drawtwister draw roll serving as the means for delivering the yarn from the treatment area.

13 Claims, 11 Drawing Figures mam PATENTED JAN 1 I974 sum 1 n; 3

. PATENTEDJAN 1 m4 SHEET 2 BF 3 m0 15o TUB/v6 P52 a PATENTEU 3.782.090

SHEET 3 BF 3 METHOD AND APPARATUS FOR PRODUCING TEXTURED YARN BACKGROUND OF THE INVENTION This invention relates to texturing yarns, and more particularly to a method and to apparatus for producing what is usually termed a bulked or stretch yarn.

For many years, synthetic yarns have been improved, or textured, by imparting a false twist in the yarn. Usually, the twist is put into the yarn while the yarn is in a heated condition, so that the effect of the twist will be permanent when the yarn is cooled.

Although the twist method produces a yarn which is of much better texture, both in appearance and feel, or hand, the yarn is far from ideal in many respects. It usually has uneven areas, which when knit produce a fabric having uneven appearance. The yarn is not as soft as could be desired, and efforts are constantly being made to improve it.

Another'problem of yarn texturing on which much effort has been expended, is the speed, or rather the lack of it, of known processes for texturing the yarn.

There are a number of systems used in texturing yarn. The most common utilizes a false twist spindle. Most of the systems employing a false twist spindle are restricted to approximately 100 yards per minute, due to the mechanical limits put upon spindle speed. Present drawtwisters operate at approximately 830 yards per minute. For a false twist spindle to apply 100 turns per inch to yarn traveling at this rate would require a spindle speed of close to 3,000,000 rpm. The maximum speed of a spindle in general use at this time is about 400,000 rpm. Thus, the false twist spindle methodcannot be used in high speed production.

Another system is that which traps the twist in yarn that is delivered from the supply package. The twist is trapped so that it backs up over a heated surface, setting the yam in the twisted condition. It is impossible to obtain any uniformity of texturing with this system.

A third method is that known as the Agilon system. This system involves heating the yarn and bending it over a sharp edge, resulting in the yarn having a coiled spring appearance. A comparison to this is the method used in curling a ribbon by drawingit over a sharp edge. Here, again, production speed is limited to about 100 yards per minute.

There is also a system of imparting twist by means of friction. This is accomplished by bringing yarn into contact with a moving surface, the movement of the surface beingat an angle to the direction of yarn movement across the surface. In known systems, the moving surface is positively driven, and precise ratio of yarn feed to friction surface speed is imperative to produce uniformity of texturing. Even if precise speed ratio can be maintained between the driving means for the friction surface and the yarn feed, yarn stretch, or elongation, will result in irregular texturing.

SUMMARY OF THE INVENTION The general object of the present invention is to provide a method and apparatus for texturing yam which will produce yarn having vastly improved characteris-. tics.

A more specific object is to provide such method and apparatus which will produce textured yarn of great uniformity.

Another object is the provision of a method and apparatus which provides twist in excess of the amount the yarn being textured can receive, to the end that each unit length of yarn textured receives a maximum and uniform twist.

A further object of the invention is to provide a method and apparatus for texturing yarn which will impart twist to yarn that has been heated and during drawing of that yarn.

It is also an object of the invention to subject the yarn to a friction twisting which begins at a maximum twist rate, reduces to a minimum twist rate, and then increases before leaving the friction surface.

Yet another object of the invention is to provide a method and apparatus for texturing yarn which includes moving a yarn about the surface of a grooved roll arranged at an angle to the yarn path to cause the yarn to first contact one surface at, or near, its periphery, move down to the center of the groove, and then up the other surface before moving out of contact with the roll.

Still a further object of the invention is to provide a method and apparatus for texturing yarn wherein a friction twisting is imparted to heated yarn as it passes from the feed rolls to the drawing roll of a drawtwister, to combine texturing with the drafting operation.

It is also an object to provide a method and apparatus for texturing yarn which is capable of producing textured yarns at speeds far in excess of those previously possible.

Yet a further object of the invention is to provide a yarn texturing method and apparatus wherein the yarn is moved across a moving friction surface, and the movement of the friction surface is caused by the pull of the yarn as it is drawn across that surface.

Other objects of the invention will become apparent from the following description of one practical embodiment thereof, when taken in conjunction with the drawings which accompany, and form part of, this specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of the feed and draw rolls of a drawtwister and the path of yarn in moving through the drawtwister and texturizing apparatus incorporated between the feed and draw rolls in accordance with the present invention;

FIG. 2 is an enlarged view of the texturizing roll with yarn wrapped about it to illustrate the path of the yarn about the roll;

FIGS. 3, 3a, 3b and 30 show diagrammatically the manner of determining the number of turns per inch imparted to the yarn as it traverses various surface areas of the roller;

FIG. 4 is a diagram showing the curve of angular friction reaction applied by the grooved roll to yarn being drawn across its surface; and

FIGS. 5, 6, 7 and 8 show various forms that the grooved roll may take.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in detail, the invention is shown, and will be described, in conjunction with a conventional drawtwister. Although the invention may be applied to a drawtwister, it is not limited to that application, but can be used in other environments as well. Therefore, in the following description the drawtwister feed roll and draw roll are to be considered, respectively, as illustrations of any suitable means to feed yarn from a package to the texturizer and to draw the yarn through the texturizer and deliver it from the machine.

Turning first to FIG. 1, the elements of a drawtwister are shown schematically, with the texturing means located between the feed roll and the draw roll. Yam 1 is drawn from a package on the usual creel (not shown) by means of the drawtwister feed roll 2. The feed roll may be in the form of a roll couple, with a pressure roll 3 pressing the yarn against the feed roll, or the roll 3 may be a guide roll and the yarn may make several turns about the feed roll 2 to provide the frictional hold to make the feed roll the holding member of the draft field. After passing through a texturizing area, indicated generally at 4, the yarn makes several laps about a draw roll 5, which is rotated at a speed relative to feed roll 2 to provide the required elongation of the yarn between the two rolls. This speed will be such that the desired yarn attenuation will be achieved while taking into account the yarn length reduction caused by the twisting in the texturing area. The drawn and textured yarn will run from draw roll 5 to any suitable collection means, such as a pick up spindle (not shown).

Although the yarn can be textured while travelling along a straight path, the length of yarn path required is considerably more than the distance from the feed roll to the draw roll, and, therefore, several direction changes are incorporated into the yarn path to provide proper length of yarn travel. Yarn from feed roll 2 will follow a downward path to a direction changing means comprising an idler roller 6 from which the yarn enters a first elongated substantially linear feed path 8 along which it travels to the first one of a plurality of tumaround-rolls 9. Feed path 8 extends through an electrically heated tubular heater of conventional construction through which the yarn moves to traverse a relatively long heating path so that the yarn is not subjected to intense heat flow in any part of the heater. Heater 15 is four or more feet in length in order to gradually heat the yarn to the temperature necessary to set the twist in the yarn while the yarn is in high speed movement through the heater.

As the'yarn leaves the first linear feed path 8, it travels over the first one of the plurality of turn-aroundrolls 9 which reverse the direction of travel of the yarn 180 without any sharp bending action on the heated yarn. The yarn then travels along a second path which includes the downstream end of a cooling zone 10 as illustrated in FIG. 1 of the drawings with the yarn passing from the cooling zone onto a texturing or twist imparting grooved roll 12 from which the yarn goes to a pair of direction changing rollers 13 and 14 onto the draw roll 5.

The tum-around-rolls 9 consist of three elongated rolls, set at an angle to one another and to the yarn travel path. This causes the yarn to traverse each of the rolls at an angle other than a right angle to the axis of the roll. Because of this, the tum-around-rolls tend to put some twist into the yarn as well as allow twist put in by the roll 12 to run back to the heater. Although the rolls do twist the yarn to some extent, this is negligible in comparison to that imparted by roll 12.

After passing around the rolls 9, the yarn moves through the cooling zone 10. This zone is of considerable importance to proper texturing, for the yarn must be cool by the time it reaches the roll 12, and the twist put in the yarn by the roll must run back to the heater zone if the twist is to be permanent. The length of the cooling zone, therefore, must be sufficiently long to assure cool yarn reaching the roll 12, yet not so long that the imparted twist will not run back to the heating zone. It has been found that a minimum of three feet is required.

It will be noted from FIGS. 1 and 2 that roll 12 has its rotational axis at an angle other than a right angle to the yarn path. The angle is such that at least a 360 wrap is obtained by the yarn, and the roll surface at all points of contact with the yarn will be moving across the yarn path in the direction to cause the yarn to twist in the desired S or Z formation. A very important feature of the roll is its mounting as an idler roll, so that its rotative motion is solely the result of the movement of the yarn along its flight. This assures roll rotation at the precise speed of yarn travel, so that twist is put into the yarn uniformly regardless of speed of yarn travel.

The grooved roll can be made of any suitable material, and both metal and plastic rolls have given good results. Plastic rolls have proven best of those tested, and rolls of polyurethane have worked better than other materials. Rolls of polyurethane of 60 to durometer, and particularly in the range of 65 to 70, which have been ground from raw stock have been very satisfactory.

The roll 12 of FIG. 2 is a V-roll and has a rather wide V shape. with considerable surface on each sloping wall 16 of the V groove. It has been found that with a groove having its side walls at an angle of approximately excellent results are obtained. The yarn 1 is shown making a full 360 turn about the roll. The yarn first contacts the roll at, or near, the periphery of one side wall of the groove, runs gradually down to the apex or bottom of the groove defined by the intersection of the side walls of the groove and follows a loop path in the apex of the groove through more than 180 while remaining in the apex which is in a plane perpendicular to the axis of rotation of the roll as illustrated in FIGS. 1 and 2. The yarn then moves out of the apex of the groove to extend on or near the periphery of the other side wall of the groove. The travel of the yarn in the loop path in the groove provides optimum rotation speed for the roll so that the extensive surface contact between the first side wall engaging the yarn as it enters the roll provides twisting action on the yarn.

In FIGS. 5, 6, 7 and 8, grooved rolls of other specific shapes have been shown. While each of these has either a V-groove, or a groove of modified V shape, each differs somewhat from the others. In FIG. 5, the roll 17 has a V-groove with side surfaces 18 which are convex rather than flat from the groove periphery to the groove bottom. The roll 19 of FIG. 6 has a V-groove which has side surfaces 20 that are concave. In FIG. 7 a roller 21 having a V-groove with side walls of different depth is shown. The side wall 22 is considerably longer than the wall 23. This means that yarn will have less frictional contact on the twist increasing exit cycle than on the twist decreasing entrance cycle. The FIG. 8 modification includes a roll 24 which has groove with side walls 25 and a bottom 26. The side walls rise straight from the bottom and curve convexly into the other perimeter. The bottom is flat and of some lateral extent. With this roll, yarn contact with the groove will not be continuous, but will be made first with the curvature at the top of the side wall, then with the bottom and then up to the top of the opposite side wall.

. It will be noted that with all of the illustrated rolls the yarn contact will be made first at a circumference of large diameter, then down to one of smaller diameter and finally up to oneof larger diameter. The amount of yarn contact with the groove will depend upon the groove shape, the amount of yarn wrap about the roll and the angle of the rotational axis of the roll relative to the yarn path.

In normal friction twisting, where the yarn is moving at right angles to the direction of movement of the friction surface, the twist put into the yarn is in direct proportion to the diameter and speed of the friction surface. In the case of the grooved roll, however, where the friction surfaces of the grooved roll do not cross the yarn at right angles, this simple ratio does not apply.

In FIG. 3, a V-roll, such as that shown in FIG. 2, has been shown schematically, and FIGS. 3a, 3b and 3c are diagrammatic views showing the roll in central vertical section, with the outer circumference being illustrated as the circumference at the lines 3a, 3b and 30, respectively of FIG. 3. The roll which is illustrated has an outer circumference which is twice the circumference'of the roll at the bottom of the groove. In all instances, the line XY indicates the line of yarn travel. In FIG. 3, the line XY shows that the yarn contacts the roll at its outer circumference, movesdown to the bottom of the groove, and up the opposite side to the outer circumference. In FIGS. 3a, 3b and 3c, the line AC represents the direction of reaction of the friction surface against the yarn at the respective points of yarn contact with the surface. The line AB represents, in all instances, oneinch of travel of the yarn. As the yarn travels this one inch, it will rotate the smaller circumference of the Vroll one inch. Since the greatest circumference of the roll is twice that of the smaller circumference, the greatest circumference will travel twice as far, or two inches. Line AC in view 3a, therefore, will be two inches. In view of this, the yarn will actually rotate the distance of line CB on its circumference. If we know the circumference of the yarn, it can be divided into the distance CB and the actual number of turns per inch will be determined. For example, with 21 denier,

4 filament yarn, at the conditions described for FIG. 3a,

the number of turns will be slightly over 250 per inch. As the contact diameter decreases, as the yarn moves toward the bottom of the V groove, the contact circumference decreases so that the distance CB decreases. This means that as the bottom of the groove is approached, the yarn is given fewer turns per inch. Conversely, as the yarn leaves the bottom of the groove and begins to move up the opposite side, the condition is reversed and the turns per inch increase until the maximum is again reached.

In FIG. 4, a chart is shown to illustrate the number of turns per inch which will be put into a yarn of 21 denier, 4 filament when moving about a V-roll which is one and one half inches in diameter at its outer circumference and three fourths of an inch in diameter at the bottom of the groove. The yam travel will be from A to B as the yarn moves from the outer circumference to the bottom of the groove, and the curve will be reversed as the yarn moves up the opposite side of the groove.

The preceding examples show that it is possible to obtain in the order of 250 turns per inch at the maximum circumference of the roller. This of course disregards slippage which is bound to occur. The yarn in question, however, will probably take no more than to turns per inch. It is obvious, therefore, that there could be as much as 33 percent slippage and still provide more turns per inch than the yarn will accept. The fact that the system is capable of providing more turns per inch than the yarn will accept, thereby producing a yarn of maximum turns per inch, probably accounts for the fact that the finished yarn is of amazing consistency.

In the above description, the texturing takes place on a standard drawtwister operating at a speed of 830 yards per minute, so that maximum production is provided, with the yarn coming from the drawtwister being both drawn and textured. As stated at the beginning of the description, the system can operate with other means for feeding the yarn to the texturing area and with othertake up means.

In the specific embodiment disclosed, the yarn has been shown as making a full wrap around the grooved roll for maximum drive and maximum friction twisting. Here, again, other arrangements may be used, for it is not necessary that a full turn be made around the roller, or that contact be made between the yarn and roll over the entire groove surface. It is contemplated that contact with the roller can be of less than 360, and that the yarn contact with the groove surface need not cover the full extent of the groove walls. It is necessary, however, that the contact be made with first one wall, then the bottom of the apex of the groove to extend in a loop in the groove as shown in FIG. 2.

The yarn which is produced by the disclosed method and apparatus has an unusually good hand and appearance, and is uniform throughout its length. The turn factor remains consistent throughout any given length of yarn.

While in the above one practical embodiment of the invention has been disclosed, it will be understood that the details of construction shown and described are merely by way of illustration and the invention may take other forms within the scope of the appended claims.

We claim:

1. A method for producing textured yarn on a draw twister having a feed roll and a draw-roll, said method comprising the steps of heating the yarn while moving the yarn along an elongated feed path of considerable length after leaving the feed roll, cooling the yarn as it moves from the area in which it is heated, drawing one portion of the yarn across a friction surface on a freely rotatable roll member mounted for rotation about an axis of rotation canted at an acute angle with respect to yarn moving onto said friction surface so that relative movement between the one portion of yarn and the friction surface causes twist to be imparted to the yarn by the friction surface which twist extends back into the area in which the yarn is heated and drawing another portion of the yarn comprising yarn that has immediately previously passed from the friction surface, along a loop path on a smaller diameter portion of the roll than said friction surface with said loop path being in a plane perpendicular to said axis of rotation.

2. The method of claim 1 wherein said freely rotatable roll includes a V-shaped groove in which one side of said groove comprises said friction surface and the apex of said groove defines said loop path.

3. The method of claim 2 wherein said V-shaped groove has a polyurethane surface.

4. Apparatus for texturing yarn comprising a yarn supply source, means for withdrawing yarn from said yarn supply source and guide means for guiding said yarn along a first path, elongated heater means extending adjacent said first path for heating yarn traveling along said first path, a yarn twisting roll means positioned downstream of said first path and heater means to receive yarn from said heater means, said yarn twisting roll being mounted for free rotation about an axis of rotation canted at an acute angle with respect to yam approaching said yarn twisting roll, said yarn twisting roll including a V-shaped groove portion defined by sloping side walls shaped so that the yarn moving onto the yarn twisting roll first engages the outer portions of one side of said groove then moves downwardly in a circumferential loop lying in the apex of said groove and extending in a plane perpendicular to the axis of rotation with the yarn in the apex of the V- shaped groove imparting maximum rotational speed to the roll to effect twisting of the yarn by the one side of the groove which twisting of the yarn extends back to said heater means.

5. The invention of claim 4 wherein said V-shaped groove has flat sloping side walls that are symmetrical with respect to the apex of said V-shaped groove and the heater means is four or more feet in length.

6. The invention of claim 5 wherein said loop path extends more than 180 about the periphery of said roll and the angle between the sloping side walls of said V- shaped groove is approximately 100.

7. The invention of claim 5 wherein said yarn twisting roll means is spaced a substantial distance from said heater means so as to permit a cooling of the yarn between the heater means and the roll means.

8. The invention of claim 7 wherein said yarn twisting roll means has a polyurethane surface having a hardness in the range of 60 to durometer.

9. The invention of claim 4 additionally including three tum-around guide roller means set at an angle with respect to each other and to the yarn travel downstream of said heater means for reversing the direction of yarn from said heater means by approximately 180 before said yarn engages said yarn twisting roll means.

10. The invention of claim 9 wherein said loop path extends more than 180 about the periphery of said roll and the angle between the sloping side walls of said V- shaped groove is approximately 11. The invention of claim 10 wherein said yarn twisting roll means is spaced a substantial distance from said heater means so as to permit a cooling of the yarn between the heater means and the roll means.

12. The invention of claim 11 wherein said yam twisting roll means has a polyurethane surface having a hardness in the range of 60 to 75 durometer.

13. The invention of claim 11 wherein said side walls are flat conical surfaces, said yarn twisting roll means is spaced at least three feet from said tum-around guide roller means and said heater means is at least four feet in length. 

1. A method for producing textured yarn on a draw twister having a feed roll and a draw roll, said method comprising the steps of heating the yarn while moving the yarn along an elongated feed path of considerable length after leaving the feed roll, cooling the yarn as it moves from the area in which it is heated, drawing one portion of the yarn across a friction surface on a freely rotatable roll member mounted for rotation about an axis of rotation canted at an acute angle with respect to yarn moving onto said friction surface so that relative movement between the one portion of yarn and the friction surface causes twist to be imparted to the yarn by the friction surface which twist extends back into the area in which the yarn is heated and drawing another portion of the yarn comprising yarn that has immediately previously passed from the friction surface, along a loop path on a smaller diameter portion of the roll than said friction surface with said loop path being in a plane perpendicular to said axis of rotation.
 2. The method of claim 1 wherein said freely rotatable roll includes a V-shaped groove in which one side of said groove comprises said friction surface and the apex of said groove defines said loop path.
 3. The method of claim 2 wherein said V-shaped groove has a polyurethane surface.
 4. Apparatus for texturing yarn comprising a yarn supply source, means for withdrawing yarn from said yarn supply source and guide means for guiding said yarn along a first path, elongated heater means extending adjacent said first path for heating yarn traveling along said first path, a yarn twisting roll means positioned downstream of said first path and heater means to receive yarn from said heater means, said yarn twisting roll being mounted for free rotation about an axis of rotation canted at an acute angle with respect to yarn approaching said yarn twisting roll, said yarn twisting roll including a V-shaped groove portion defined by sloping side walls shaped so that the yarn moving onto the yarn twisting roll first engages the outer portions of one side of said groove then moves downwardly in a circumferential loop lying in the apex of said groove and extending in a plane perpendicular to the axis of rotation with the yarn in the apex of the V-shaped groove imparting maximum rotational speed to the roll to effect twisting of the yarn by the one side of the groove which twisting of the yarn extends back to said heater means.
 5. The invention of claim 4 wherein said V-shaped groove has flat sloping side walls that are symmetrical with respect to the apex of said V-shaped groove and the heater means is four or more feet in length.
 6. The invention of claim 5 wherein said loop path extends more than 180* about the periphery of said roll and the angle between the sloping side walls of said V-shaped groove is approximately 100*.
 7. The invention of claim 5 wherein said yarn twisting roll means is spaced a sUbstantial distance from said heater means so as to permit a cooling of the yarn between the heater means and the roll means.
 8. The invention of claim 7 wherein said yarn twisting roll means has a polyurethane surface having a hardness in the range of 60 to 75 durometer.
 9. The invention of claim 4 additionally including three turn-around guide roller means set at an angle with respect to each other and to the yarn travel downstream of said heater means for reversing the direction of yarn from said heater means by approximately 180* before said yarn engages said yarn twisting roll means.
 10. The invention of claim 9 wherein said loop path extends more than 180* about the periphery of said roll and the angle between the sloping side walls of said V-shaped groove is approximately 100*.
 11. The invention of claim 10 wherein said yarn twisting roll means is spaced a substantial distance from said heater means so as to permit a cooling of the yarn between the heater means and the roll means.
 12. The invention of claim 11 wherein said yarn twisting roll means has a polyurethane surface having a hardness in the range of 60 to 75 durometer.
 13. The invention of claim 11 wherein said side walls are flat conical surfaces, said yarn twisting roll means is spaced at least three feet from said turn-around guide roller means and said heater means is at least four feet in length. 